Traumatic brain injury (TBI) is most likely to damage the frontal lobes and anterior tips of the temporal lobes. The portions of the frontal lobes so affected are known to subserve complex functions, including attention, memory consolidation, regulation of emotion, behavioral planning and inhibition. These functions, directly and indirectly, increase the likelihood that a person with TBI could become involved with the criminal justice system. While there are no definitive studies of the co-occurrence of TBI and criminal behavior, existing research suggests that TBI may be more prevalent among inmates than the general population. The Ohio State University (OSU) TBI Identification Method is being developed to provide a reliable and valid method of detecting multiple aspects of a lifetime history of TBI. This instrument has been designed consistent with CDC guidance on TBI incidence and prevalence surveillance, and the structured interview has been refined to maximize accuracy and minimize confounding influences. One preliminary study has supported its inter-rater reliability and suggested its utility for predicting consequences of TBI. We propose to use the OSU TBI Identification Method to accomplish the following aims: AIM 1: Establish the test/re-test reliability of summary indices drawn from a structured interview for detecting prior TBI in an adult, state prison population. AIM 2: Determine whether summary indices demonstrate predictive validity for the consequences of TBI in this population. Development of a reliable and valid method of eliciting a history of TBI is an initial, mandatory step to determining the prevalence of TBI in incarcerated populations. A tool that measures multiple dimensions of TBI history may prove useful for eventually identifying promising avenues of intervention.